The present invention is an improvement to industrial humidifiers of the type disclosed in U.S. Pat. No. 4,940,475 to Yaeger. With reference to the Yaeger patent, and in particular FIGS. 2 and 3, it can be seen that the humidifier has blades 70 in a bypass damper. Blades 70 are rotated to vary the degree that air can be bypassed. When it is desired that no air is bypassed, the blades are rotated to close the bypass and prevent air flow. As can be appreciated, a seal along the length of the blades is desirable to insure that when the blades are in the closed position no air is able to pass around the closed blades.
However, it has been found that on larger humidifier units where the length of the blades can approach 9 feet in length, it is difficult to obtain a uniformly tight seal over the full length of the blades because the torque of the actuator which turns the blades and the air pressure tend to cause the blades to bow at the middle. This bowing prevents a tight seal which allows some air to bypass the humidifier thereby lowering the system's ability to add humidity to the air stream.
Therefore a need exists for an adjustable seal for the blades that can be adjusted to tightly seal along the length of the blades despite bowing of the blades.